Endo Flashcards
The initial colonizing bacteria is collectively known as ___ plaque and predominantly consists of ___ ___ microorganisms. Namely ___ and ___.
Supragingival
Gram-positive facultative
Acintomyces viscosus
Streptococcus sanguinis
What is the earliest manifestation of a carious lesion?
Change in enamel opacity
Change in enamel opacity will eventually lead to further tooth surface destruction nd formation of tooth decay if not addressed immediately
What is pulp hyperemia?
A type of reversible pulpitis that describes an accumulation of blood in the pulp space with vascular congestion due to a physical, chemical, or microbial insult
Pain from a hyperemic pulp has what 4 characteristics?
Brief
Low intensity
Not spontaneous
Does not remain following stimulus removal
Bleaching an inadequately obturated tooth can lead to ___. Why?
Symptomatic apical periodontitis
Bleaching agents may leech into the root canal treated tooth and beyond into the apical portion, causing periapical swelling/pain.
What is the treatment of choice for teeth with non-vital pulps resulting from trauma?
RCT
Cracks typically extend ____ deep into dentin in posterior teeth. They typically begin to propagate in the region of the ___.
Mesiodistally
Marginal ridges
When is a pulpectomy indicated for a primary tooth? When is a pulpotomy indicated?
Pulpectomy - no tooth mobility but the infection might already have reached the pulp
Pulpotomy - primary teeth having suffered accidental pulp exposure or bacterial attack that only affects the coronal portion of the pulp
Note that indirect pulp capping is not indicated for primary teeth but is used for permanent teeth with a cavity or caries approximating the pulp
In periapical cemental dysplasia, the presence of an intact ___ along the apical portion of the involved tooth also shows that the radiolucency did not come from an infected tooth.
Lamina dura
What is the likely outcome of an intruded maxillary incisor seen in a ten-year-old child that occurred due to trauma? Why?
Necrosis, because the blood vessels supplying the pulp are impeded
Why do intrusion of primary teeth do not typically result in necrotic pulp?
Because the blood flow is better because of the open apex.
90% of intruded primary teeth re-erupt after two to six months
What is the correct shape of access preparation for a maxillary central incisor?
Triangular
Why is pulp capping and pulpotomy more successful in newly erupted teeth than fully matured teeth?
They have open apices which allows for better circulation.
In what cell layer does the nervous plexus of raschkow reside?
The cell-rich layer which is between the core of the pulp and the cell-free zone. Axons of the plexus lose their myelin sheath as they penetrate the cell-rich and cell-free zones to make synaptic contact with the odontoblasts cell body in the pulp or odontoblastic process within the dentinal tubules
What is the role of the plexus of raschkow?
Monitors painful sensations as well as mediation of inflammatory events and subsequent tissue repair
In a young patient, a ___ mm pulp exposure is considered too large for ____ and apexogenesis should be attempted instead.
2
Direct pulp capping
In apexogenesis, a ___ is performed and the chamber is filled with a layer of ____ in order to ___
Pulpotomy
MTA (mineral trioxide aggregate)
Leave the root intact and allow the finishing of root formation
What is apexification?
Involves the addition of calcium hydroxide to the canal after the pulpal tissue is completely removed. Application of calcium hydroxide induces calcification across the apex and formation of a calcific barrier. RCT therapy is completed following calcification of the apex.
Apexification is contraindicated in what three cases?
A vital pulp
Very short roots
Marginal periodontal breakdown
What is the access shape for a maxillary 1st molar with four canal orifices?
Blunted triangular-shaped or rhomboidal
The MB and DB orifice are most commonly located near each other.
What is the best way to allow for complete cleaning and shaping of the root canal system?
Obtainment of straight line access
In RCT, filing should be performed ___mm [short/long] of the radiographic apex and obturated ___mm [short/long] of the radiographic apex.
- 5-1mm short
0. 5-1mm short
True or false… failure rates are high in cases where the root canal is filed and obturated up to or beyond the radiographic apex.
True
The maxillary 2nd premolar typically has __ root with __ canal(s) in __% of cases.
1
2
50%
Maxillary 1st molars typically have __ canals which are…
4
MB, MB2, DB, P
Mandibular premolars typically present with __ canal(s) and ___ root(s).
1
1
What material is is indicated to dissolve, soften, or otherwise remove gutta percha?
Chloroform
This is used in retreatment cases
EDTA is a ___ solution used to…
Chelating
Remove inorganic components of a root canal such as smear layer
True or false… eugenol and IRM is germicidal
True
Recapitulation is utilized during ___ ___ to accomplish what?
Step back enlargement
To remove dentin filings from the apical segments that are not removed by irrigation
Performing recapitulation after each file prevents preparation errors such as…
Apical transportation
Incomplete instrumentation
Underfilling during obturation
True or false… sodium hypochlorite irrigation is the most important factor for disinfection of a root
False… complete mechanical debridement is the most important factor
What surface of what root of what toot is the most likely to undergo strip perforation during root canal instrumentation
Distal surface of mesial root of mandibular first molar (also the mesial surface of the distal root)
Why is zinc oxide predominantly found in most root canal sealers?
It has antibiotic properties and serves to prevent reinfection of the root canal
Eugenol, is sometimes used in conjunction and serves to sedate and soothe the periradicular nerve tissues to decrease postobturation sensitivity
What are the color codes for files?
10 Purple 15 White 20 Yellow 25 Red 30 Blue 35 Green 40 Black 45 White
MB2 is located ___ to the orifice of MB1 and is observed in ___ of patients.
Lingual
~98%
The MB2 canal often times joins with the MB1 canal before the apex is reached
True or false.. reaming action will enlarge a root canal and make it more round in shape
True
Rotating files in a ___ direction will force debris apically, while ___ rotation will direct debris coronally.
Counterclockwise
Clockwise
What four things is sodium hypochlorite used for?
Dissolve organic matter
Kill bacteria
Lubricate the canal
Irrigate the canal
in the case of root amputation for periodontal reasons, which is performed first, RCT or periodontal therapy?
RCT and resection followed by periodontal therapy
What is the function of calcium hydroxide in apexification?
Creation of high pH conducive to bone growth and helps mineralized the root apex.
Pins should be placed __mm from the DEJ. They should be placed __mm into the amalgam. Pins [should/should not] be bent.
1mm
2mm
Should not
True or false… a post enhances the resistance of the restoration to lateral forces
True
What is the most likely adverse effect of internally bleaching an endodontically treated tooth with superoxide?
External cervical root resorption
The presence of a ____ barrier over the root-filling material may help to reduce the instances of external cervical root resorption when superoxide is used for internal bleaching if it is at least __mm in thickness.
Glass ionomer
4mm
True or false… the walking bleach technique using sodium perforate is NOT associated with external cervical root resorption
True, it is NOT associated
True or false… internal bleaching weakens tooth structure.
False
The rule of thumb for post preparation is that you prepare the canals so that ___ of the root has gutta percha remaining (or about __mm)
1/2
5mm
A depth of at least ___mm into the root canal is essential for the retention of an amalgam restoration in an endodontically treated tooth.
3mm
True or false.. teeth with sinus tracts do NOT require antibiotics. Why?
True, teeth weigh sinus tracts do not require antibiotics because the infection drains
What should be done If a sinus tract does not health within one month after RCT?
Root-end surgery should be performed
What is the walking bleach technique?
Intracoronal bleaching technique which utilizes a mix of sodium perforate and anesthetic or steril water to create a paste to be sealed into the pulp chamber for 14-21 days
The walking bleach technique should be repeated as necessary until the desired tooth color is attained
This technique is used on teeth that have already undergone endodontic therapy and does not lighten staining due to previous amalgam placement
External root resorption may occur in the walking bleach technique if what happens?
The canal is not obturated properly or if 30% hydrogen peroxide (superoxol) is used
____ is used for vital tooth bleaching (external bleaching)
Carbamide peroxide
Endodontic treatment of a tooth should result in the osseous regeneration of the bone around the apex of the tooth and subsequent healing of the periapical lesion. The healing is gradual and may take ___ to ___ to resolve.
6 months to 1 year
Why are barium salts added to gutta percha?
To make it radiopaque
Zinc oxide (70%) Barium sulfates (5%) Waxes, resins, gutta percha (24%)
Evaluating obturation requires assessment of what three things?
Fit of gutta-percha points
Density of gutta-percha fill
Level of gutta-percha in the canal
Periapical bone regeneration usually occurs at a rate of about ___mm per month
1.2
In posterior teeth, cracks typically extend in a ___ direction deep into dentin. They typically begin to propagate in the region of the marginal ridges
Mesiodistal
A fracture in the ___ third of the root would have the best prognosis.
Apical
How do you confirm a diagnosis of subluxation?
Bleeding from the gingival sulcus confirms the diagnosis. Subluxation is an injury to the tooth-supporting structures, resulting in increased mobility but does not displace the tooth
An 8 year old boy presents to your office with a traumatized #8 that no longer responds to electric and thermal vitality tests. What should be done? Why?
Re-evaluation in 2 weeks.
Traumatized immature teeth may give false reading with thermal and electrical vitality tests. Although their blood supply may still be intact, their nerve may not respond. As circulation is restored to the tooth, responsiveness may return after 2 weeks.
True or false… a tooth that is replanted must first be stabilized in its proper position before any treatment can be performed (RCT)
True
A 10 year old patient presents to your office with a horizontal root fracture in the middle third of the root of tooth #8. The tooth is mobile and tests vital to cold. What should be done? Why?
Splint the tooth and observe. (2 weeks)
Pulp necrosis is rare for the apical segment because the circulation remains intact following the trauma. Of all cases, 25%-75% remain vital after horizontal root fracture.
Why might a mid-root fracture become more visible after RCT? What is the prognosis?
The sealer flows out into the space between the fractured pieces.
Prognosis of treating a mid-root fracture is relatively poor
When treating teeth with horizontal fractures that have limited mobility, the remaining coronal portion of the tooth root and its crown should undergo RCT and the apical portion should be removed via apical surgery
What is the best decision when an instrument is separated in the apical third after cleaning and shaping have occurred?
Do not attempt to remove, and proceed to obturation.
The prognosis of the tooth will be considered more favorable if the infected dentin has already been debrided from the canal. It will also be considered more favorable the more apically the instrument separation occurred.
Why is an electric dental pulp vitality test contraindicated just after a traumatic injury?
A negative response may be temporary because the neural transmission was interrupted (false negative) - it may take about 2 months to respond to electric pulp testing again. Electric pulp testing gives the status of the pulpal nerve fibers, not the blood supply of the tooth.
Another term for replacement resorption is ___
Ankylosis
True or false… sealer contains disinfectant properties
False
Immediately after tooth trauma, which clinical finding is the least informative for determining the prognosis of the tooth. Why?
Tooth vitality because the lack of pulpal response in a tooth can be attributed to the injury within the tooth’s nerve fibers. An immediate vitality test might be inaccurate, so subsequent vitality tests should be conducted to evaluate pulp status. At least 8 weeks might pass before the tooth displays normal pulp response
How long should you wait after tooth trauma to receive an accurate pulp vitality test?
8 weeks
Development of pulp necrosis is most commonly seen in which type of dental trauma?
Intrusive luxation.
When is intentional replantation indicated?
When the apical half of the root of a tooth cannot be engaged, cleaned, and shaped. The procedure is done by extracting the apical segment and replanting the coronal segment that recently received RCT
Splinting should be [rigid/flexible] and should last for ___ weeks to prevent replacement resorption (AKA ___). What will happen if splinting lasts too long?
Flexible
2
Ankylosis
The portion of the tooth that was resorbed is replaced by the healing bone, causing ankylosis
What is the best outline shape for the access preparation of a mandibular 1st molar with 3 canals?
Trapezoidal (follows the position of the cusp tips)
____ can differentiate into secondary odontoblasts which secrete ____
Undifferentiated mesenchymal cells
Tertiary dentin
Pulp lacks ____ which limits its ability to cope with infection
Collateral circulation
What is sclerotic dentin?
Calcification of tubules in response to slowly advancing caries or aging
Reactionary dentin is reaction to ___ damage (AKA secondary dentin)
Minor
Reparative dentin (AKA ____) is repair for ___ damage
Tertiary dentin
Major
List the histologic zones of pulp from dentin inwards
Predentin
Odotnoblastic layer
Cell-free zone of Weil
Cell-rich zone
Pulp core
What is the difference between hyperalgesia and allodynia?
Hyperalgesia = heightened response to pain
Allodynia = reduced pain threshold, pain due to stimulus that does not normally provoke pain
Preauricular pain often refers from ____ since both share V3 innervation
Mandibular molars
What chemical is endo ice? It is what temperature?
Dichlorodifluoromethane
-30C
How do you properly use endo ice?
Chilled cotton pellet is applied immediately to middle third of facial surface of crown for 5 seconds. Make sure tooth is throughly dried before hand.
Intensity and duration of response provide information about pulpal diagnosis
True or false… electrical pulp testing is more reliable than cold testing
False. It is the least reliable pulp vitality testing method.
Electrical pulp testing indicates if there are ____ present in the pulp, but does not provide any information about the ____ supply to the pulp which is the true indication of pulp vitality. It is contraindicated in what circumstance?
Vital sensory fibers
Vascular supply
Cardiac pacemaker
In what two ways can you get a false positive with electrical pulp testing?
Accidentally touch gingiva
Tooth isn’t sufficiently dried
In what two ways would you get a false negative result with electrical pulp testing?
Recent trauma to the tooth
Excessive calcification of the canal
True or false… pulp necrosis is usually asymptomatic but not always. Can be partial or total
True
Pulp necrosis is due to long-term interruption of ___ to the pulp. Crown ___ May accompany pulp necrosis in anterior teeth.
Blood supply
Discoloration
What is the key way to diagnose an asymptomatic apical periodontitis case?
Apical radiolucency and confirmation of pulpal necrosis
How is a chronic apical abscess diagnosed?
Draining sinus tract, usually without discomfort.
What is the key feature of symptomatic apical periodontitis?
Pain on percussion
A 20 file is ___ in color. If it has 02 tapper, It is ___mm in diameter at the tip (D1), __mm in diameter at D2, and __Mm at D16.
Yellow
.2mm
.22
.52
What is significant about D16?
It is where the cutting flutes end
Sodium hypochlorite dissolves [organic/inorganic] material
Organic
EDTA dissolves [organic/inorganic] material
Inorganic
What is the primary bacteria for primary endodontic infections?
Bacteroides
What is the primary bacteria for failed endodontic treatment?
Enterococcus faecalis
Enterococcus faecalis is a gram [positive/negative] facultative [aerobic/anaerobic] bacteria
Positive
Anaerobic
What is trephination?
Surgical opening in hard tissue to release exudate and pressure
In periapical microsurgery, ___mm of root tip is resected. This is called an apicoectomy. A bevel of __degress is ideal. Then, ___mm is prepared and filled with ____
3mm
0-10
3mm
MTA
What is a ledge? Why do they occur?
An artificial irregularity created on surface of root canal wall
Lack of proper straight line access, inadequate glide path, occur more frequently in curved canals, long canals, and narrow canals, inadequate irrigation or lubrication
How do you bypass a ledge?
Use smaller instrument to work around it (renegotiation)
Put a small bend in the file to help bypass the ledge
Why do instruments separate in a canal?
Excessive force
Jumping up a file size too fast.
Inadequate irrigation or lubrication
Not replacing files often enough
True or false… flexible NiTi files are more likely to fracture
True
What do you do when an instrument has separated?
Use a smaller instrument to bypass
Is it a better prognosis to have the file separate early or later in the instrumentation process? Why?
Later, because most of the bacteria has been removed at this point
Strip perforation is often due to ___. Where are the “danger zones” located?
Excessive coronal flaring
Distal of mesial root and mesial of distal root because there is a concavity at the furcation
Does root perforation have a better prognosis if it is mor coronal or more apical?
More apical has better prognosis
What are some signs of a perforation?
Immediate hemorrhage or sudden pain
How do you repair a root perforation?
Internal repair with MTA
Describe the Ellis classification system class 1 - class 6
Class 1 - enamel only
Class 2 - enamel and dentin
Class 3 - enamel, dentin, and pulp
Class 4 - traumatized tooth that has become non-vital
Class 5 - luxation
Class 6 - avulsion
What is an uncomplicated fracture?
Fracture without pulp involvement (Ellis class 1 and class 2)
What is the treatment if the fracture only involves enamel? What if it involves enamel and dentin?
Smooth edges
Restore
What is the treatment of choice if the complicated fracture presents to your office in less than 24 hours?
Direct pulp cap
What is the treatment of choice when a patient has a complicated fracture and comes to your office within 24-72 hours?
Cvek pulpotomy
What is the treatment of choice if the patient has a complicated fracture and presents to your office in 72 hours or later?
Pulpotomy
In a horizontal root fracture, the ___segment is displaced and the __ segment is not displaced. What radiographs should be taken?
Coronal
Apical
3 PAs and 1 occlusal
What is the ideal healing of a horizontal root fracture?
Calcific healing at the fracture site - calcific metamorphosis can reattach fragments in close proximity via calcification
What is the treatment of choice in a vital horizontal root fracture case? Coronal fracture? Midroot fracture? Apical fracture?
Splint ASAP
Coronal fracture - rigid splint for 6-12 weeks
Midroot fracture - flexible splint for 3 weeks
Apical fracture - flexible splint for 2 weeks maximum to avoid ankylosis (has the best prognosis)
Which is better a complete transverse horizontal fracture or an oblique fracture?
Oblique
In a horizontal root fracture case, which segment is most likely to be necrotic?
Coronal segment
Necrosis of apical segment is very rare
What is the treatment of choice for a concussion case?
Let the tooth rest.
What is subluxation?
No displacement, increased mobility
PDL rips and bleeds
What is the treatment of choice for a subluxation?
Flexible splint for 1-2 weeks
There is a ___% chance of necrosis in a subluxation case with closed apices. It is [more/less] favorable in cases with open apices
6%
More
What is the treatment of choice in an extrusion case with an open apex? What if it was a closed apex? Which has a more favorable prognosis?
Reposition, flexible splint, monitor
Reposition, flexible splint, RCT if needed
Open apex
Closed apices have a 65% chance of necrosis
In lateral luxation, the crown is usually displaced ___ and the root apex is displaced ___. What is the treatment of choice? __% chance of necrosis in cases with closed apices.
Palatally
Labially
Same treatment options as extrusion
80%
What is the treatment of choice in the case of an intrusion with an open apex? What about a closed apex?
Open - allow to reerupt
Closed - reposition, flexible splint, RCT
There is a __% chance of necrosis in a case of intrusion with a closed apex.
96%
What is the treatment of choice in an avulsion case with a closed apex and the EADT (extraalveolar dry time) is less than 60 minutes?
Reimplant, splint
What is the treatment of choice in an avulsion case with an open apex and the EADT (extraalveolar dry time) is less than 60 minutes?
Reimplant, splint, no RCT but apexification at first sign of infected pulp
What is the treatment of choice in an avulsion case with a closed apex and the EADT (extraalveolar dry time) is greater than 60 minutes?
Reimplant, splint, RCT
What is the treatment of choice in an avulsion case with an open apex and the EADT (extraalveolar dry time) is greater than 60 minutes?
May or may not reimplant, splint, RCT, plan for implant
Calcium hydroxide has a pH of ___. How does it work?
12.5
Cauterized tissue and kills bacteria
It stimulates secondary odontoblasts to repair with dentinal bridge formation
How does MTA work? It is composed of what three minerals?
Stimulates cementoblastes to produce hard tissue
Calcium, silicon, aluminum
True or false… MTA has bismuth oxide as an opacifier. It has a long setting time of 3 hours. It sets in the presence of moisture. It is antimicrobial. And it is a great sealing agent because it is nonresorbable
True
What are the 3 three’s of MTA?
3 minerals - calcium, silicon, aluminum
3 hour setting time
3 advantages: sets in presence of moisture. Antimicrobial. Nonresorbable (great sealing agent)
When is an indirect pulp cap indicated?
Deep caries that is approximating the pulp. Not touching the pulp but very close (less than a mm away)
A direct pulp cap is indicated if there is a mechanical exposure of
2mm
6 weeks
When would you do a pulpotomy on a permanent tooth?
Traumatic exposure that occurred over 72 hours ago
In a pulpotomy, formocresol is placed directly over the pulp canals. What then occurs?
Fixation, which renders it resistant to enzymatic breakdown. This will then cause the underlying pulp to undergo coagulation necrosis. Hopefully the very ends of the canal remains vital
What are the contents in Buckley’s formocresol?
19% formaldehyde
35% cresol
15% glycerine
31% water
It is a bacteriocidal and a fixative (fixes the pulp tissue, devitalizes it, and makes it resistant to enzymatic breakdown)
In a pulpectomy, ___ is placed in the crown, and ___ is placed in the root.
ZOE
CaOH
Which primary teeth are most difficult to perform pulpectomies on? Why?
Primary first molars. They have lots of accessory canals
If a primary tooth is symptomatic is it usually best to extract or perform a pulpectomy?
Extract
In apexogenesis, __ or __ is placed on healthy or diseased pulp to allow the body to make a stronger root.
Calcium hydroxide
MTA
True or false… apexogenesis technically includes any indirect pulp cap, direct pulp cap, cvek pulpotomy, or pulpotomy performed in an immature permanent tooth to allow further root development
True
When is apexogenesis contraindicated?
Avulsed, nonrestorable, severe horizontal fracture, and necrotic teeth.
When is apexification done instead of apexogenesis?
If the tooth root is not fully developed yet the tooth is NONVITAL
This doesn’t allow the root to finish developing (it can’t cause its nonvital), instead this allows the root end to close.
Disinfection of root canal followed by induction of an acceptable apical barrier.
CaOH or MTA is placed at base of canal after dead or dying pulp is removed
Cracked tooth syndrome has pain on ____. It is sensitive to ___. It is sometimes completely asymptomatic.
Biting and on release
Cold and hot
True or false… dyes and transillumintaion are more helpful for identifying cracks than radiographs. Tooth slooth on each cusp can aid in location of the crack.
True
What is the treatment for a cracked tooth with a healthy pulp? What about diseased pulp?
Splint with band and observe. Or crown
Conservative RCT and crown
A vertical root fracture starts ___ and progresses ___
Apically
Coronally
Vertical root fractures are most likely to occur after ____
Cementation of a post or excessive condensation forces on an overprepared canal (most common)
How are vertical root fractures often found?
Isolated probing defect at site of fracture
J-shaped or teardrop radiolucency
What is the treatment of choice for a vertical root fracture of a single rooted tooth? What about a multi-rooted tooth?
Extract
Extract or respect affected root
What is the ideal treatment option for a vertical root fracture?
Extraction
In a true combined perio-endo lesion. Which is treated first, the endo or the perio?
Treat endo first, then perio
What surface of which root is most likely to undergo strip perforation in RCT of a mandibular molar?
Distal area of mesial root
